Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jan. 31, 2015
Class Of Stock [Line Items]
Repurchase authorization, shares			5,000,000
Cash dividends paid to common stockholders	$ 57	$ 47
Cash dividend paid per share	$ 0.915	$ 0.74
Dividends declared to noncontrolling interests	$ 14	$ 16
Dividends paid to noncontrolling interests	$ 13	$ 16
January 2015 Share Repurchase Authorization [Member]
Class Of Stock [Line Items]
Common stock shares repurchased	2,934,176
Shares remaining available for repurchase under the current authorization	2,065,824